P0304 on 2011-2018 Dodge Challenger: Cylinder 4 Misfire Causes and Fixes

What's Unique About the 2011-2018 Dodge CHALLENGER

For the 2011-2018 Dodge Challenger, the cause of a P0304 code depends heavily on the engine. While common ignition part failures are frequent across all engines, early 3.6L Pentastar V6 models (2011-2013) are known for a specific left cylinder head defect that causes this exact code. Chrysler issued a warranty extension (X56) for this issue, which involves checking for excessive cylinder leakage and replacing the head if necessary. For Hemi V8 engines (5.7L, 6.4L), a faulty Multi-Displacement System (MDS) solenoid can be a cause, as cylinder 4 is one of the cylinders deactivated by MDS. On these Hemi engines, lifter failures ('Hemi tick') can also progress to a wiped camshaft lobe and a persistent P0304 misfire.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle. 👇

Symptoms You May Notice

• Check engine light is on or flashing
• Rough or shaky idle
• Engine hesitation or stumbling during acceleration
• Noticeable loss of power
• Reduced fuel economy
• Smell of unburned fuel from the exhaust
• Audible ticking or tapping sound from the engine (especially relevant for Hemi lifter issues or Pentastar rocker arm failure)

Most Likely Causes

1. Failed Left Cylinder Head (2011-2013 3.6L V6 Only) 🔴 High Probability → Shop Engine Cylinder Head A known manufacturing defect affected the left cylinder head on early Pentastar 3.6L engines, causing premature wear of valve guides and seats. This leads to a loss of compression and misfires specifically on cylinders 2, 4, and 6. Chrysler issued TSB #09-002-14 and extended the warranty to 10 years or 150,000 miles (code X56) for this specific problem.
   How to confirm: A professional mechanic needs to perform a cylinder leak-down test on cylinders 2, 4, and 6. Per TSB 09-002-14, if leakage on any of these cylinders is 25% or greater, the cylinder head is confirmed to be faulty. The presence of P0302 or P0306 alongside P0304 is a very strong indicator.
   Typical fix: Replace the left cylinder head assembly with the updated part. 🎬 Watch: A detailed walkthrough of the 3.6L cylinder head repair. This is a major repair that was often covered by the extended warranty.
   Est. part cost: $500-$1200
2. Faulty Ignition Coil 🔴 High Probability → Shop Ignition Coil Coil-on-plug ignition systems are common failure points on modern engines due to constant exposure to high heat cycles. This is a very frequent cause for a single-cylinder misfire across all Challenger engines.
   How to confirm: The easiest way to diagnose a bad coil is to swap the ignition coil from cylinder 4 with another cylinder (e.g., cylinder 2 on a V6 or cylinder 6 on a V8). Clear the codes and drive. If the code changes to the cylinder you moved the coil to (e.g., P0302 or P0306), the coil is bad.
   Typical fix: Replace the faulty ignition coil. It's often recommended to replace them in sets if they are high-mileage, especially on the V6 where three coils are under the intake manifold.
   Est. part cost: $30-$90
3. Worn or Fouled Spark Plug 🟡 Medium Probability → Shop Spark Plug Spark plugs are a regular maintenance item. Hemi V8 engines use two plugs per cylinder (16 total), increasing the chance of a single plug failing. Valve cover gasket leaks can also leak oil into the spark plug tubes, fouling the plug and causing a misfire.
   How to confirm: Remove the spark plug(s) from cylinder 4 and inspect it. Look for a worn electrode, heavy carbon buildup, oil fouling, or a cracked insulator.
   Typical fix: Replace the spark plug. It is best practice to replace all spark plugs at the same time (6 for V6, 16 for V8).
   Est. part cost: $10-$30 per plug
4. Clogged or Faulty Fuel Injector ⚪ Low Probability → Shop Fuel Injector Fuel injectors can become clogged with deposits over time or fail electronically, preventing the correct amount of fuel from entering the cylinder.
   How to confirm: A mechanic can perform a fuel injector balance test. A DIY method is to listen to the injector with a mechanic's stethoscope; it should have a consistent clicking sound. You can also swap the injector with another cylinder to see if the misfire follows, but this is more labor-intensive.
   Typical fix: Replace the faulty fuel injector.
   Est. part cost: $50-$150

Rare But Worth Checking

• Failed MDS Solenoid (5.7L & 6.4L Hemi V8 Only): The Multi-Displacement System (MDS) deactivates cylinders 1, 4, 6, and 7 to save fuel. If the solenoid for cylinder 4 gets stuck or fails, it can disrupt valve timing and cause a persistent misfire on that cylinder, even when MDS is not active. The presence of codes like P3425 is a strong indicator of this failure.
• Camshaft/Lifter Failure (Hemi V8 Engines): → Shop Engine Camshaft The notorious 'Hemi tick' can be a sign of a failing lifter roller bearing. If ignored, the failed lifter can grind down the corresponding camshaft lobe, leading to insufficient valve lift and a permanent misfire on that cylinder. This is a severe mechanical failure requiring extensive repair.
🎬 Watch: This video explains why Hemi lifters fail and tick.
• Failed Rocker Arm (3.6L V6, especially post-2013): → Shop Engine Rocker Arm Later Pentastar engines, while free of the cylinder head defect, are known for rocker arm bearing failure. This causes a ticking noise ('Pentastar Tick') and prevents the valve from opening correctly, resulting in a misfire. The fix often involves replacing all 24 rocker arms and lifters.

Diagnosis Steps

1. Read the code with an OBD-II scanner and check for any other pending or stored codes, especially P0300, P0302, or P0306.
2. Identify the engine in your Challenger (3.6L V6, 5.7L Hemi, 6.4L Hemi) and its cylinder layout. On the 3.6L V6, 🎬 Watch: See the Pentastar V6 cylinder layout and firing order. the front bank is the right bank (cylinders 1-3-5 front to back) and the rear bank is the left bank (cylinders 2-4-6 front to back). Cylinder 4 is the middle cylinder on the driver's side (left bank). On Hemi V8s, the passenger side is the right bank (cylinders 2-4-6-8 front to back) and the driver's side is the left bank (cylinders 1-3-5-7 front to back). Cylinder 4 is on the passenger side, the second cylinder from the front.
3. If you have a 2011-2013 3.6L V6, be highly suspicious of the cylinder head issue. Check vehicle history for warranty work and reference TSB 09-002-14. A cylinder leak-down test is the next logical step before replacing parts.
4. For all other engines, or if the leak-down test passes, start with the ignition system.
5. Swap the ignition coil from cylinder 4 with an adjacent, easily accessible cylinder (like cylinder 2 or 6).
6. Clear the codes and test drive the vehicle. If the misfire code moves to the new cylinder (e.g., P0302), you have a bad ignition coil.
7. If the code remains P0304, inspect the spark plug(s) in cylinder 4. Check for wear, damage, or fouling. Replace if necessary.
8. On Hemi V8s, listen carefully for a distinct ticking sound at idle, which could indicate a lifter or MDS solenoid issue.
9. If the coil and plug are good, the next step is to check the fuel injector. This may require professional diagnosis.
10. If all else fails, a compression test and cylinder leak-down test should be performed to check for internal mechanical engine problems like bad valves, piston rings, or a failed head gasket.

Parts You'll Likely Need

• Ignition Coil (OEM #3.6L V6: 5149168AJ; 5.7L/6.4L Hemi: 68238603AA) — This is one of the most common failure points for a single-cylinder misfire.
  Trusted brands: Mopar, NGK, Denso
  OEM price range: $50-$90
  Aftermarket price range: $30-$75
• Spark Plug (OEM #3.6L V6: SP149125AF (or Champion SP149125AE); 5.7L Hemi: SPLZFR5C11; 6.4L Hemi: SP149212AC) — A worn or fouled spark plug is a frequent and simple cause of a misfire.
  Trusted brands: NGK, Champion
  OEM price range: $15-$30
  Aftermarket price range: $10-$25
• Left Cylinder Head Assembly (3.6L V6, 2011-2013) (OEM #RL141353AC (remanufactured), 68141353AC (new). These supersede earlier part numbers.) — This is the specific fix for the known manufacturing defect on early Pentastar engines that causes P0304.

Related Codes That Often Appear With This One

• P0300 — If the misfire is intermittent or starting to affect other cylinders, a P0300 (Random/Multiple Cylinder Misfire) code may appear alongside P0304.
• P0302, P0306 — On 2011-2013 3.6L V6 models, these codes often appear with P0304, strongly indicating the known left cylinder head failure, as all three cylinders (2, 4, 6) are on the affected left bank.
• P3425 — On a 5.7L or 6.4L Hemi V8, this code for 'Cylinder 4 Deactivation Control Circuit' along with P0304 is a very strong indicator of a failed MDS solenoid or lifter for cylinder 4.

Technical Service Bulletins (TSBs) & Recalls

• 09-002-14 REV. B: Outlines the diagnosis (cylinder leak-down test >25%) and repair (replace left cylinder head) for MIL illumination with codes P0300, P0302, P0304, or P0306 on 2011-2013 3.6L Pentastar engines.
• D-14-12 (USA) / X56: The warranty bulletin that officially extended coverage for the left cylinder head on affected 2011-2013 vehicles to 10 years or 150,000 miles.

Platform-Specific Known Issues

• 2011-2013 3.6L Pentastar V6: Defective Left Cylinder Head: → Shop Engine Cylinder Head These models are subject to a known defect in the left cylinder head that causes premature valve guide and seat wear, leading to loss of compression and misfires on cylinders 2, 4, and 6. Chrysler issued Technical Service Bulletin 09-002-14 REV. B and an extended warranty (X56, 10 years/150,000 miles) to address this. Diagnosis requires a cylinder leak-down test.
• 5.7L & 6.4L Hemi V8: Cam/Lifter Failure and MDS Issues: These engines can suffer from camshaft and lifter failure, often preceded by a ticking noise ('Hemi Tick'). This can cause persistent misfires on any cylinder, including cylinder 4. Additionally, the Multi-Displacement System (MDS) which deactivates cylinder 4, can have solenoid failures that also trigger a P0304 code.
• Post-2013 3.6L Pentastar V6: Rocker Arm Failure: → Shop Engine Rocker Arm While the cylinder head issue was resolved, later 3.6L engines are known to develop a ticking noise from failed rocker arm bearings. This mechanical failure prevents proper valve operation and directly causes misfires. The recommended fix is often to replace all rocker arms and lifters.

Mechanic-Grade Diagnostic Values

• Cylinder Leakage (2011-2013 3.6L V6) — expected: Less than 25%. Failure: Leakage of 25% or greater on cylinders 2, 4, or 6 confirms a faulty left cylinder head.
• Ignition Coil Secondary Resistance — expected: 6,000 to 10,000 Ohms. Failure: A reading outside this range indicates a failed internal winding.
• Fuel Injector Resistance (3.6L V6) — expected: Approximately 12.0 - 12.5 Ohms. Failure: A significantly higher (open circuit) or lower (shorted) reading indicates a failed injector coil.
• Fuel Pressure (at fuel rail) — expected: Approximately 43.5 psi (3 Bar). Failure: Low fuel pressure can cause lean misfires across multiple cylinders, but can sometimes affect a single cylinder.
• Spark Plug Gap (General) — expected: 0.024 to 0.071 inches (verify specific engine). Failure: An incorrect gap can cause a weak or inconsistent spark.

Hidden / Shadow Codes Worth Checking

• Mode $06, TID $83: Live misfire counters for each cylinder. This allows a technician to see the number of misfire events detected by the PCM, even if they aren't frequent enough to set a hard code. It's crucial for diagnosing intermittent misfires. (see via An advanced OBD-II scanner (like BlueDriver or a professional tool like wiTECH) that can access Mode $06 test results.)

Scan Tool Commands That Help

• wiTECH or other advanced scanner: Cylinder Contribution / Balance Test — Use this function to actively test the power contribution of each cylinder. The tool will command changes and monitor crankshaft speed to determine if cylinder 4 is underperforming compared to the others, confirming a consistent misfire.
• wiTECH or other advanced scanner: Fuel Injector Kill — This bidirectional command allows the user to manually disable the fuel injector for cylinder 4. If there is no change in engine RPM or smoothness, it confirms that cylinder 4 was not contributing in the first place.
• wiTECH (Dealer Tool): PCM Flash / Software Update — If misfires (P0304) are known to occur primarily during cold starts, check for Technical Service Bulletins (TSBs) that call for a PCM software update. This can resolve logic errors causing false misfire detection.

Wiring & Ground Locations

• Cylinder 4 Ignition Coil Connector — On the 3.6L V6, cylinder 4 is the middle cylinder on the driver's side bank. On Hemi V8s, it is the second cylinder from the front on the passenger side bank.. This is the primary connection point for the ignition coil. The two key wires to test here are the ASD (Auto Shutdown) relay output, which should have 12V+, and the coil driver signal wire from the PCM, which is a pulsed ground signal.
• Cylinder 4 Fuel Injector Connector — Located on the fuel rail, plugging into the injector for cylinder 4.. A damaged connector or wiring here can cause a P0304. On some models, the injector control wire from the PCM is pin 11 on one of the main PCM connectors. This is critical for checking wire integrity from end to end.
• Main Engine/PCM Grounds — Typically located on the engine block, cylinder head, and chassis near the battery.. A corroded or loose ground can cause low voltage to the ignition coils or injectors, leading to a weak spark or insufficient fuel delivery and causing intermittent, hard-to-diagnose misfires.

Real Owner Repair Stories

• DTech Engineering YouTube Channel (2019 Dodge Challenger (Hemi V8)) — Check engine light with codes P0204 (Injector Circuit/Open) and P0304.
  ❌ Tried (didn't work) Initial visual inspection found rodent damage to the injector wiring harness for cylinders 2 and 4. The wires for cylinder 4 were chewed and shorting together. Repairing the wires did not resolve the codes.
  ✅ What actually fixed it A load test of the cylinder 4 injector control wire from the PCM connector to the injector connector showed the wire itself was good. This isolated the fault to the Powertrain Control Module (PCM). The injector driver circuit inside the PCM was damaged by the initial wiring short. Replacing the PCM was the final fix.
• TOPDON USA 'Problem Solved' Case Study (2015 Chrysler Town & Country (3.6L Pentastar V6, same engine family)) — Persistent engine misfire (P0301 in this case, but applies to P0304).
  ❌ Tried (didn't work) Replacing crankshaft sensor, Replacing camshaft sensors, Replacing ignition coils and spark plugs, Removing and servicing one cylinder head at a machine shop
  ✅ What actually fixed it Advanced diagnosis using an oscilloscope and an in-cylinder pressure transducer revealed an intermittent loss of compression due to a mechanical valvetrain problem. The root cause was a failed rocker arm, a known issue on this engine. The correct fix was to replace all rocker arms, valve springs, and lifters.

"I Checked Everything" — The Actual Cause

• In a documented case, a P0304 was ultimately caused by a failed injector driver inside the PCM. This was triggered by an external event (rodent damage shorting the injector wires). A smoke test would have been clean, and swapping the coil, plug, and injector would not have worked because the control module itself was the point of failure. The diagnosis required a load test of the wiring to prove the harness was good before condemning the expensive PCM.

When the Usual Fixes Don't Work

• While ignition components are the most common cause, a persistent P0304 after replacing the coil and spark plug should immediately shift diagnostic focus. On a 2011-2013 3.6L, the next step must be a leak-down test to check for the known cylinder head defect. On a Hemi V8, it could point to a failing MDS solenoid or a more serious lifter/camshaft issue. In one documented case on a 2019 Challenger, the root cause was a failed PCM driver that was damaged by a wiring short, a fix that would be missed by simple parts swapping.

OEM Part Supersession History

• Various older part numbers for the 3.6L left cylinder head → RL141353AC (remanufactured), 68141353AC (new) — The original cylinder heads had a design defect causing premature valve guide and seat wear. The new part numbers are for the corrected design.

Model Year Variations Within This Range

• 2011-2013: Models with the 3.6L V6 built on or before July 25, 2012, are susceptible to a left cylinder head defect that is a primary cause of P0304.
• 2014-2018: The 3.6L V6 in these years is not affected by the cylinder head TSB, but is more known for rocker arm bearing failures causing similar misfire codes.
• 2015: The Challenger received a major interior and exterior facelift. The 5-speed automatic was replaced by the ZF 8-speed automatic across all engine options, which can affect diagnostics and drivetrain-related codes.